Not applicable.
Not applicable.
The present invention generally relates to an ultrasound system and in particular to a personal computer (PC) based ultrasound system which utilizes multiple processors controlled to operate in parallel and to share processing responsibilities.
Ultrasound systems have been used for many years in the field of radiology by physicians to examine various areas of humans, such as the heart, arteries, organs, a fetus, and the like. Ultrasound systems typically include two primary sections, a front end and a back end. The front end section includes one or more ultrasound probes for scanning an area of interest within a patient. Conventional front end sections also include a beamformer hardware unit that enables transmission of ultrasound signals into the patient and acquires echo ultrasound signals therefrom. The front end section passes acquired echo signals to the back end section which performs signal processing upon the acquired echo signals. The back end section converts the processed echo signals to a format displayable on a CRT and displays the echo signals in a desired format, such as a graph, a 2-dimensional image, a 3-dimensional image, a black and white image of anatomic structure (B-mode image), a colorized image of moving fluid (color flow image) and the like.
In the past, the front and back end sections of ultrasound systems were constructed in a hardware intensive manner utilizing multiple hardware boards, each board of which performed predetermined dedicated operations. In past ultrasound systems, dedicated hardware boards were included to perform signal processing and separate dedicated hardware boards were provided to perform scan conversion, which is the task of translating the incoming data from its beam coordinate space, usually polar, to Cartesian coordinates space. In addition, past ultrasound systems required a separate central processor which controlled various dedicated hardware boards. The central processor did not perform signal processing or scan conversion. Instead, the central processor primarily performed system control operations, such as setup functions to configure the hardware boards when the system was turned on and management of the dedicated hardware boards throughout operation.
More recently, ultrasound systems have been proposed which utilize digital signal processors (DSP) to carry out signal processing and scan conversion. One or more DSPs are programmed to cooperate to perform signal processing. The DSPs dedicated to signal processing are housed on a set of one or more printed circuit boards. A separate set of DSPs housed on a separate set of printed circuit boards are programmed to perform scan conversion. However, even in systems using DSPs, each set of DSPs is dedicated to specific processing operations. Hence, a DSP configured to perform Doppler signal processing cannot perform scan conversion. In addition, ultrasound systems which utilized DSPs continue to require a separate central CPU to maintain system control.
More recently, in the early 1990s, the assignee of the present application introduced ultrasound systems based on the architecture of a personal computer (PC). These ultrasound systems were referred to as the ESI5000(trademark) and Synergy(trademark) systems. The ESI5000(trademark) and Synergy(trademark) systems included DSP boards for signal processing and a central processor for controlling overall operation of the ultrasound system. The central processor of the PC was used to carry out setup operations and to control the DSP boards. The central CPU in the Synergy(trademark) system also performed scan conversion of Color Doppler images from polar coordinates to Cartesian coordinates. Also, the ESI5000(trademark) and Synergy(trademark) systems used separate beamformer hardware in the front end subsystem.
However, conventional ultrasound systems have experienced limitations. In particular, conventional ultrasound systems require the use of a central processor to carry out dedicated operations including system setup and overall control and separate beamformer hardware. Conventional systems also require at least some hardware boards and/or DSP boards to carry out dedicated signal processing such as spatial and temporal filtering, tissue motion filtering, Doppler processing and the like. The hardware boards and DSP boards programmed for signal processing are unable to do any other operations besides signal processing. During operation, the central CPU and beamformer may remain idle while a dedicated DSP performs signal processing in the conventional system. Likewise, the dedicated DSPs and beamformer remain idle throughout setup of the system, while the central CPU must perform all setup operations. Consequently, conventional systems have been unable to realize the full processing power of the beamformer, DSPs and central CPU.
A need remains for an improved ultrasound system to overcome the above-identified difficulties. It is an object of the present invention to meet this need.
It is an object of the preferred embodiment of the present invention to provide an ultrasound system which operates multiple CPUs in parallel to carry out all ultrasound functions, such as setup, system control, beamforming, signal processing and scan conversion.
It is a further object of the present invention to provide an ultrasound system which maximizes the use of available processors in the system.
It is a further object of the present invention to provide an ultrasound system which avoids the need to dedicate functions to any given processor.
It is a further object of the present invention to provide an ultrasound system which divides ultrasound operations into tasks assignable to separate processors.
It is yet another object of the present invention to provide an ultrasound system that recommends a preferred division of operations into tasks between processors to maximize use of processor time.
It is another object of the present invention to provide an ultrasound system that simplifies overall processing by serially stepping through the ultrasound operations.
It is another object of the present invention to provide an ultrasound system enables high priority functions, such as user-interface service, to interrupt sub-operations assigned to one or more CPUs, in order to enhance user response time.
It is another object of the present invention to provide a front end subsystem that does not require separate beamformer hardware.
It is a corollary object of the present invention to provide an ultrasound system that performs beamforming operations through software.
These and other objects of the present invention are provided by an ultrasound system operating on a personal computer architecture comprising multiple processors controlled to operate in parallel to share ultrasound functions of the system. The multiple processors are controlled by software to share the operations associated with system setup, system control, scanning, data acquisition, beamforming, user interface service, signal processing, and scan conversion. The ultrasound system utilizes management software which divides operations associated with each function (such as signal processing and scan conversion) into parallel sub-operations or tasks. Each task is assigned by the operating system to a unique CPU. Any of the CPUs may be capable of performing any of the tasks. The CPUs operate in parallel to carry out the assigned tasks. Once all of the CPUs have completed the assigned tasks, the system may serially advance to the next ultrasound function.